Hydraulic vehicle power transmission



April 7, 1942. W,4 BLACK u v 2,279,019

HYDRAULIC VEHICLE POWER TRANSMISSION Filed Nbv. 27, 1959 asheetS-sheet 1 E2 a se Fi .3. 5'/ g Inventor" Willy Black,

yi-iis ttorrley W. BLACK HYDRAULIC VEHICLE POWER TRANSMISSION April 7, 1942.

Filed Nov. 27, 1939 2 sheets-sheet 2 Fig] Inventor: Willy Blas by j l-lls Attohey Patented Apr. 7, 1942 HYDRAULIC' VEHICLE vrovvrza TRANSMISSION willy Black, Berlin-nalensee, Germany, assigner to'Genel-al Electric-Companm-a 'corporation of New York Application November Z7, 1939, Serial'No. 306,369 e l .'In Germany December8,` 1938 f My invention relates to automotive vehicle transmissions of the hydraulic type' and more particularly to the type including hydraulic gear such as described in United States Patents 1,199,359 and 1,199,361 issued to Fttnger.

One object of my invention is to provide an improved power transmission whereby stalling of the prime mover under varying -vehicle operat-v ing conditions is substantially eliminated.

For a better understanding of my invention together with other and further objects thereof reference is had to the following description taken in connection withv the accompanying drawings, and its scope will be pointed out in the appended. claims.

In the accompanying drawings Fig. l illustrates in vertical cross section a vehicle power transmission built in accordance with my invention. Fig. 2 is a diagram indicating the operating characteristics of the transmission illustrated in Fig. 1.. Figs. 3 and 4 illustrate enlarged sectional and plan views, respectively, of a control mechanismapplied to the transmission of Fig. 1; Fig. 5 is a fragmentary sectional view of a detail of Fig. 1; Fig. 6 illustrates a modification of a control element of Fig. 1 and Fig. 'I is aside view of a vehicle having a hydraulic transmission provided with the modified control element illustrated in Fig. 6.

The transmission illustratedv in Fig. 1 consists generally of a hydraulic torque converter I 0, a mechanical coupling II and a reversing gear I2. The converter includes a pump wheel I3 mounted upon a drive shaft I4, a turbine wheel I5 and a guide wheel I6. The turbine wheel I5 is attached to a housing I1 of the mechanical cou- 'pling II and is centered about the shaft I4 by its hub I5'. This housing I1 is integral with andr is supported by a driven shaft I8 which is a hollow shaft projecting through and supported by The bearing I9 is in turn sup-'- a bearing I9. ported in a wall 2I.of a transmission housing 22. The guide wheel I6 is in the form o f a casing surrounding the pumpA and turbine wheels and forming with these wheels a fluid circuit in which the uid, preferably oil, is circulated to transmit energy between the pump and turbine wheels. The guide wheelis supported at one end by a sleeve23 rotatable about -and supported on shaft I4. It is supported at its other end by .a

unidirectional brake 24 av fragment of which,

looking in the direction of arrow 5 in Fig. 1, is

shown in Fig. 5. This brake may be .of any suitable construction which permits the wheel to a simple form of such brake comprising rollers 25 mounted between a sleeve 26,l which is integral withl the-guide wheel I6, and teeth 21 I .mounted ona wall 28 of the casing 22.' In operationV the rollers are wedged between the teeth and the sleeve 26 to stop the guide wheel when there is a force` tending to turn the guide wheel in a clockwise direction looking in the direction of arrow 5 in Fig. 1. When this turning force is reversedthe guide wheel moves the rollers into g the notches between the teeth and thereby is freed to rotate in that direction.

Clutch II consists of platesV 29 attached to the inner surface of the casing I1 and of co.operat ing plates'a attached 4to a hub 3| mounted on the drive shaft I4. 'I'he clutch plates are normally out of engagement with each other so that the turbine wheel rotates free of the drive shaft. A piston 32 is provided in theA end of the casing I1 to eifect an engagement of the two sets of clutch plates. The piston 32 is provided with a stud shaft 33 normally projecting into the hollow shaft I8. This shaft and the piston are held in this position by a spring 34 placed under compression between a disk 35, attached to the end of the shaft 33, and the end wall separating the casing AI1 from the hollow shaft I8. The piston is moved forward to effect an engagement of the clutch plates by oil supplied under pressure to the hollow shaft I8.

Reversing gear I2 includes a gear 36 attached to the end of the hollow shaft I8. This gear supports the end of a'driven shaft 31 upon which a gear 38 is mounted.` VThe gear 38 is keyed to shaft 31 but is axially movable relatively to the shaft. The gears 36 and 3'8 are provided with vclutch teeth 4U and 4I on adjacent surfaces,

respectively, whereby Ia directmechanical connection may be made between the shafts I8 and '31 by sliding the gear '38 upon the shaft 31, until theteeth 40+-'4I engage. Reverse operation of the shaft 31 -is obtained -by moving the gear 38 by any suitable means (not shown) to disengage the teeth 40 and 4I and into engagement with va gear 39 of the reversing gear train. The com-l plete train ofl reversing gears includes the gear 42 mounted on'a jack shaft 43 and engaging the gear 36. A second gear 4 4 also'mounted on jack shaft 43 engages a gear 39 which in turn drives the gear 33. The driven shaft 31 is supported at. its outer end ina bearing 45 located in the end vwall of the reverse gear casing 46 and is providedwith a suitable coupling plate 31'. The

v jack shaft 43 is supported at one end vin a bear- 1 rotate in only one direction. Fig. A5' `illustrates an 'ing' 41 in the .end wall of the reverse gear housing 45 and is supported at the other end in a bearing 48 in the wall 2l of the housing 22. The gear 89 is mounted on a suitable'shaft in back of shaft 43 and is not visible in this view.

Operating fluid, preferably oil, is supplied to the hydraulic gear and to the mechanical clutch piston by a positive displacement pump 5U driven by a shaft 5I through a worm pinion 52 attached to the end of the shaft and through a co-operating worm gear 58 mounted on the drive shaft I4. The pump is provided with a suitable pressure adjusting relief valve 54 through which oil is supplied to a conduit 55', 55 leading to the A hydraulic gear and to a conduit 55 leading to the clutch piston. The function of the relief valve 54 is to regulate the opening to the conduit 55. Any suitable valve may be used for this purpose. In Fig. 6 an example of such valve is shown diagrammatically. In this valve a piston 54' is positioned by an adjusting screw 54" to `regulate the passage of oil from the valve housing to the conduit 55. The piston 54' is positioned'to restrict the opening `into the conduit 55' and thereby enables the pump to build up a pressure in the conduit 58.

A spring 54" placed between the piston 54 and the adjusting screw 54" enables the oil to move the piston relatively to the screw in response to oil pressure variations thereby to vary the opening into conduit 55 and to maintain a constant oil pressure in the conduit 55.

'I'he conduit 55', 55 conducts oil to the hydraulic gear. It is connected to an annulus 51 surrounding the shaft I4 at a point between the lworm gear 58 and the end of sleeve 28. Oil space is provided in the sleeve 28 so that oil may ow from the annulus 51 into the guide wheel. I8 and from there through a clearance space between `the guide wheel and the pump wheel into the hyable space. In the illustrated example it is conducted to the conduit 55 and into the hydraulic gear huid-circuit.

The conduit 56 directs oil through a control mechanism 50 into the hollow shaft I8 for operating the clutch piston 32. 'Ihe conduit 58 is, for this purpose, connected to the wall 2| in which a channel 8| is provided to connect the end of the conduit 55 with an annular chamber 52 in the bearing I9. Oil flows from this channel into' the hollowshaft I8'through openings 53 registering with the annular channel 62. Oil pressure builds up in back of the piston 82 by oil flowing from the hollowl shaft through a clearance space around shaft 83 in the dividing wall between the clutch casing I1 and thehollow shaft I8.

In the diagram of Fig. 2 the oil pressure P delivered by the pump 50 as well as the quantity Q of oil delivered are plotted against n the number o f revolutions of the pump, the number of revolutions being proportional to the speed of the drive shaft I4. 'I'he quantity Q is a straight line characteristic increasing in substantially direct proportion to the revolutions n. At increasing speedof the pump the total output thereof flows through the conduit 59 while constant pressure is maintained in conduit 56. 'I'he pressure P rises as the square of the speed until the full pressure isreached at-a corresponding speed n.

I'he pressure thereafter remains constant. The' fluid Q', which is the total volume discharged by the pump atv the maximum pressure, iiows through the by-pass valve 58 into the conduit l5. For the closing of the mechanical coupling a minimum pressure P' is requiredland is obtainable at a speed of n". Y

During operation of the vehicle with the clutch I I infclosed position, the oil pressure falls as the vehicle slows down. When the speed of the drive shaft falls below the value n, the clutch is permitted to openand thereby to release the motor so that it may operate the vehicle through the hydraulic gear. In so doing the motor load is reduced and a stalling of the motor due to overload is avoided. The value n" is determined by the settingl of the valve 58.- This valve is adjusted manually and maybe adjusted to obtain clutch operation within a predetermined speed range.

The operator of the vehicle is given control of the clutch and hydraulic gear operation, by the device 60 illustrated in Figs. 3 and 4. Fig. 3 is a cross sectional view of the control device, and Fig. 4 is a plan elevation thereof. It includes a manually operated lever 10, which is moved to its dotted line position (Fig. 4) when it is desired to start the vehicle or to operate the vehicle at low speed, that is, through the torque converting hydraulic gear. This same lever is moved to its full line position illustrated in Fig. 4

-for high speed operation, that is, through the mechanical coupling. The lever 10 is mounted on the square end 1| 'of a shaft 12, the shaft 12 being the valve stem of a shut-olf valve in the conduit 58. This shaft 12 is turned to shut oif the pressure inthe clutch cylinder and thereby open the clutch when the lever 1li is moved to its dotted line position. The shaft is turned to open the valve and thereby turn on pressure inthe conduit when the lever is moved to its full line position as shown in Fig. 4.

Between the lever 10 and the housing 18 an auxiliary lever 14 is loosely mounted on the shaft 12. The casing 13 carries projecting walls 15 and 15 in which suitable bearings are provided to support the shaft 12. 'Ihis casing 13 also contains a.

vwith a projection 8| which may be engaged by the lever' 10 to move the auxiliary lever in a counter-clockwise direction against the tension of a spring 82 supported at' one end by a lug 83- onthe,casing 13 and attached at its other end to the lever 14. This spring tends to move the lever inra clockwise direction. In operation, the lever 10 is moved to its full line position, and also moves the auxiliary lever 14 with it, when it is desired to operate the vehicle with the mechanical clutch closed. If the proper speed is available, the pressure in conduit 58 is sufllcient to raise the pistonV against the pressure of spring 19 and thereby movethe pin 80 into'the path of the auxiliary lever 14. Under this condition, the spring 82 cannot move the auxiliary lever. If, however, the lever 10 is in the full line'position of Fig. 4 at a time when the vehicle speed is suddenly reduced so that-there is insuillcient speed its upper position, the pin 80 will move out of the path of the auxiliary lever 14, and the spring 02 will, accordingly, move the auxiliary lever and the lever 'I0 through the` projection 8|, into the dotted line position. It is, therefore, possible for an operator to move the lever` '|0 to either of its two positions but it is impossible for an operator to leave the lever '|0 in this full line position of Fig. 4, his attempts to Nchange the vehicle operation, by--inoving the lever '|0 to this position, being made ineffective as soon as he releases the lever unless the proper oil pressure-l ever, it is desirable to place this adjustment under the constant control of the vehicle operator,

rod |03. The fuel regulator is operated by a pedal 95 projecting above the frame |00 and rearwardly of the engine in position to be moved by the foot of the driver. The pedal 95 is connected to one end of a bellcrank |04 which is pivoted at |05 and to the other two'ends of which the rods 94 and |03 are connected respectively. The engine drives the vehicle through a transmission such as described in Figs. 1 to 5. Itis provided with the adjustable valve of Fig.` 6,- the rod-` 94" What I claim as new and desire to secure by l LettersPatent of the United States is:.

1. In avvehicle transmission, the combination l of a hydraulic gear, a mechanical coupling, presand it is more convenient to place this valve under the control of an operating lever of the motor vehicle, such as the engine accelerator pedal, for example. The accelerator pedal is movedin response to load conditions, and is, therefore, a convenient means for automatically adjusting the valve 58. -In Fig. 6, the valve 58 is illustrated as having a rotatable core 90 in which a port 9| cooperates with the port 92 in the body of the valve and controls the area of the fluid opening in accordance with its rotation. This core element 90 is, therefore, provided with a lever 93, by means of which it may be rotated, the end of the'lever being attached to a rod 94 which is moved in accordance with the movement of the engine accelerator pedal 95 illustrated in Fig. 7. In the position shown, the valve by-passes a minimum amount of fluid and represents the idling position of the accelerator pedal. In the illustrated example the minimum iluid'by-pass position of the valve is the complete shut-off position. When the accelerator is depressed, the lever 93 ismoved clockwise, thereby increasing the amount of fluid by-passed through the bypass conduit 59, and thereby lowering the speed at which the clutch is permitted to open. With this operation of the valve 58, the operation of clutch is under the control of the speed of speeds and light load with the clutch closed.

This condition would exist when running on level ground at low speeds. Under a constant setting of the valve 58, the low speed of the shaft I4 would require an opening of the clutch. In view of the light load on shaft |4,.this. is not necessure operated means for operating said coupling, a pumpdriven from a shaft of said transmission and arranged to generate uid pressure responsive to the speed of said shaft, conduit means connecting said pump to said hydraulic gear and to said coupling operating means, manual means for controlling the operation of said transmission,v through said hydraulic gear and through said mechanical coupling alternately, and means responsive to the fluid pressure generated by said pump for effecting a change-over from mechanical coupling operation to hydraulic gear operation g a fluid connection between said pump and said operating means, manual control means for controlling the fluid in said connection and thereby effect a transmission of power through said mechanical coupling and through said hydraulic torque converter alternately, and means responsive to the iiuid pressure delivered by said pump for effecting a change-over from mechanical coupling operation to hydraulic gear operation when 3. In avehicle transmission, the combination ofl a hydraulic coupling of the Fttinger typ'e provided -with a drive and a driven' shaft, a pump wheel mounted on said drive shaft, a turbine wheel connected to said driven shaft, a guide sary. On. the other hand, at higher speeds, where the load on shaft I4 is high due tothe weight of the vehicle, or' possibly the grade over which the vehicle is traveling is steep, it is desirable to opcrate with the clutch open. In view of the accelerator pedal being at its lowest position, and

therefore, the valve 58 being at its maximum .by-

pass setting, the high speedof the shaft |4 is' ineffectual to produce enough oil pressure to keep the clutch closed. The accelerator pedaL-therefore, is a convenient means for regulating .the

by-pass valve, or in other words, for determining the operating points at which the clutch is to be closed and opened respectively. Fig. 7 is aside end ofvwhich is mounted an engine|0|, 'a fuel l carburetor |02 v and a fuel regulating lever and wheel mounted for rotation in lonly one direction, land a uid enclosed by said three wheels for transmitting energy between said drive'and driven shafts4 a* mechanical coupling between said drive and driven shafts, a` fluid operated pisfollow-up lever, said'locking means preventing the f operationof said follow-up lever when a pre- Y determinedjspeed of Vsaid drive 'shaft is obtained wherebyunder such conditions the manual lever will remain in theposition for mechanical couy pling, operation. v 1- l' v In a power plant for an automative vehicle the combination of an engine, a fuel control pedal therefor, a power transmissionv connectedbetween With this arrangement, the speed saidengine and the drive shaft of said vehicle including a driving and a driven shaft, a hydraulic gear operable to' transmit power between said shafts, Ia mechanical coupling' means reof saidshaft, and means responsive to the operation of said fu'el control pedalV for changing the adjustment of said pressurefvadilsmgmeans whereby' the operation *ofjsaid mechanical'coupling 4v'x'ru'aans is effected at predetermined 'different speeds responsive to the speed of said shaft and modified by the fuel valve operation for said engme.\.

5. iahydraulic gear transmission, the comj operated means to the open clutch position, and means responsive tothe fluid pressure inl said bination of a hydraulic torque converter provided with a drive shaft, a pump wheel mounted thereon, a guide wheel, a driven shaft and a turbine wheel connected thereto,V a mechanical clutch connected between said drive shaft and said driven shaft, a hydraulically operated piston for controlling the operation of said clutch, a -uid pump operated bysaid drive shaft for supplying fluid to said hydraulic gear and to said clutch piston, manually operated means for controlling the opening and the closing of said clutch, means tending to'move said manually hydraulic gear for; making ineffective said lastmentioned means when said fluid pressure reaches `a predetermined -value proportional to a predev termined speed of'said drive shaft.

` WILLY BLACK. 

